Fev1/Fvc Ratio Calculator

The FEV1/FVC ratio is a crucial measurement in pulmonary function testing, aiding in the diagnosis and assessment of respiratory conditions such as chronic obstructive pulmonary disease (COPD) and asthma. This calculator simplifies the process of determining this ratio, offering users a quick and convenient tool.

Formula: The FEV1/FVC ratio is calculated by dividing the forced expiratory volume in one second (FEV1) by the forced vital capacity (FVC), and then multiplying by 100 to express the result as a percentage.

How to Use:

  1. Enter the value for FEV1 (forced expiratory volume in one second) in liters.
  2. Input the value for FVC (forced vital capacity) in liters.
  3. Click on the “Calculate” button to obtain the FEV1/FVC ratio result.

Example: Let’s say you have an FEV1 value of 2.5 liters and an FVC value of 3.0 liters. After entering these values into the calculator and clicking “Calculate”, you will find that the FEV1/FVC ratio is 83.33%.


  1. What is the FEV1/FVC ratio? The FEV1/FVC ratio is the ratio of the forced expiratory volume in one second (FEV1) to the forced vital capacity (FVC) expressed as a percentage.
  2. What does a low FEV1/FVC ratio indicate? A low FEV1/FVC ratio often suggests obstructive lung diseases such as COPD or asthma.
  3. Is a high FEV1/FVC ratio normal? Yes, a higher than normal FEV1/FVC ratio may indicate good lung function.
  4. What is a normal FEV1/FVC ratio? A normal FEV1/FVC ratio is typically above 70% in adults.
  5. Can the FEV1/FVC ratio change? Yes, it can change due to various factors such as age, smoking, and lung diseases.
  6. Is the FEV1/FVC ratio different for men and women? Generally, there’s no significant difference in the ratio between men and women.
  7. Can this calculator be used for pediatric patients? While this calculator is primarily designed for adults, it can be used for pediatric patients with appropriate adjustments for age and size.
  8. What units should I use for FEV1 and FVC? Both FEV1 and FVC should be entered in liters.
  9. Can I use this calculator on mobile devices? Yes, this calculator is optimized for use on both desktop and mobile devices.
  10. Is this calculator accurate? This calculator provides accurate results based on the input provided.

Conclusion: The FEV1/FVC ratio is a fundamental parameter in assessing lung function, particularly in diagnosing respiratory conditions. This calculator offers a convenient way to determine this ratio, aiding healthcare professionals and individuals in understanding their respiratory health.